514 THE HIGHER ANTHROPOIDS 



convey the impression of a balanciniz; mechanism upon which less demand is 

 made than in liu' lower, more strictly arl:)()real |)riinates. The orang is 

 altogether slower in its locomotion, l)oth m its arboreal pursuits and on those 



FIG. 233. OKANG-OUTANG. LEVEL OF THE \HST1BLLAK NUCLEI. 

 CTT, Central Tegmental Tract; cow, Ventral Spinocerebellar Tract; ici', Inferior Cerebellar Peduncle; 10, 

 Inferior Olive; mf. Mesial Fillet; nar. Nucleus Arciforinis; nd, Deiters' Nucleus; nr. Nucleus of Rolando; 

 NSC, Nucleus of Schwalbe; n8. Acoustic Nerve; pd, Predorsal Bundle; pl, Posterior Longitudinal Fasciculus; 

 PY, Pyramid; rep, Reticular Formation; rst, Rubrospinal Tract; spt. Spinothalamic Tract; trd. Descend- 

 ing Trigeminal Tract; Tuu, Tuberculum Acusticum. [Accession No. 199. Section 285. Actual ,Sizc 

 20 X 12 mm.] 



rarer occasions when it (^oes u|)on the ground. I he dillert lux- in all prol)al)ility 

 is slight, for the efficacy of the balancing mechanism set'ins to be laiily well 

 standardized. What one s])ecies requires most m some speciali/ed dux'Ction 

 is less essential to other loinis. An axcraging ol balancing requirements seems 

 to equalize the development of eciuilibratory structures. 



In the ventrolateral portion ol the section, the ctphalic t'\trt'init\ oi 

 the inferior olive appears (10), and mesial to it the bundles constituting 



